Wet spinning process



3,457,343 WET SPINNING PROCESS Otto E. van Lohuizen and Pieter Paulnsma, Arnhem, and Gaspard L. F. van Kinschot, Rozendaal, Netherlands, assignors to Algemeine Kunstzijde Unie, N.V., Arnhem, Netherlands, a corporation of the Netherlands No Drawing. Filed Aug. 22, 1966, Ser. No. 573,852 Claims priority, application Netherlands, Aug. 28, 1965, 6511263 Int. Cl. [901d 5/06; Dtllf 7/00 U.S. Cl. 264-184 2 Claims ABSTRACT OF THE DISCLOSURE A process for the wet spinning of threads from poly- 2,6-disubstituted paraphenylene ethers comprising extruding a solution of said ether in an aliphatic halohydrocarbon into a coagulation bath consisting essentially of 590% by volume of said halohydrocarbon and 9510% by volume of a liquid in which the ether is insoluble and which is miscible with said halohydrocarbon.

The invention relates to a novel process for the wet spinning of threads from poly-2,6-disubstituted paraphenylene ethers, and to the resulting products.

A process of this type is known broadly from British Patent No. 930,993.

By poly-2,6-disubstituted paraphenylene ethers are meant the polyparaphenylene ethers that are mentioned in said British patent and which in at least a considerable proportion of the phenylene group carry substituents at least in the 2-position and the 6-position. These substituents may be chosen from the group consisting of lower alkyl groups, aryl groups or halogen atoms. Since poly- 2,6-dimethylparaphenylene ether, which will hereinafter also be referred to as PPO, is at the moment the most prominent representative of said group of polymers, the invention will be described primarily with reference thereto. It will be clear to the man skilled in the art that other representatives of the group of poly-2,6-disubstituted paraphenylene ethers will give similar results.

Just as in the case of other polymers, the properties of yarn manufactured from poly-2,6-disubstituted paraphenylene ether are strongly dependent on the spinning conditions used.

It has been found that from a poly-2,6-disubstituted paraphenylene ether it is possible to obtain a yarn which has properties making it particularly suitable for textile applications if the process is so carried out that a spinning solution of poly-2,6-disubstituted paraphenylene ether in an aliphatic halohydrocarbon is extruded into a coagulation bath consisting of 5 to 90% by volume of said halohydrocarbon and 95 to 10% by volume of a liquid in which the poly-2,6-disubstituted paraphenylene ether is insoluble and which is miscible with said aliphatic halohydrocarbon.

The resulting yarns are strong and supple, they have a very attractive dull luster which is strongly suggestive of that of natural silk; and the woven and knitted fabrics made therefrom may be washed in very hot water (for instance of 100 C.) without becoming unduly creased. Articles made of polyethylene terephthalate, which has so far been considered having the most favorable crease resistance, are in this respect far inferior to the products 3,457,343 Patented July 22, 1969 according to the present invention. The yarns obtained by the present invention are therefore particularly suitable for the manufacture of wash and wear garments.

The spinning solution, which consists of a solution of the polymer in an aliphatic halohydrocarbon, may have a widely varying composition.

For example, in addition to an aliphatic halohydrocarbon or a mixture of halohydrocarbons, the solution may contain other solvents for the polymer. Or it may contain liquids in which per se the polymer does not dissolve; but the amount thereof must of course not be so large that the polymer will not dissolve in the mixture thereof with the halohydrocarbon used. In the process according to the present invention it is essential that as spinning liquid use be made of a solution of PPO in a liquid which contains more than 50% by weight of an aliphatic halohydrocarbon.

Examples of suitable aliphatic halohydrocarbons are the following compounds or mixtures thereof: chloroform, trichloroethylene, dichloromethane, l-chloro-Z- fiuoro-ethane, and the like. Aliphatic chlorohydrocarbons are preferred, but aliphatic fluorohydrocarbons and chlorofluorohydrocarbons are also within the scope of the invention.

The most favorable results are obtained if the spinning liquid is a solution of PPO in chloroform and the spinning solution contains 10 to 45 g. polymer per ml. chloroform; the use of such a spinning liquid is therefore preferred.

If as solvent for the PPO use is made of chloroform and as coagulation or spinning bath a mixture of ethanol and chloroform, then the regeneration of the spinning bath can be carried out very economically by distilling the used spinning bath, whereupon an azeotrope of chloroform, ethanol and water distills over which separates at room temperature into a chloroform-rich phase and an ethanol-rich phase. The chloroform-rich phase, the composition of which is about 94.3% by weight of chloroform, 5.5% by weight of ethanol and 0.2% by weight of Water, may without further treatment be used as solvent for the polymer in the preparation of the spinning solution. The ethanol-rich phase may be used in the preparation of fresh spinning bath.

The spinning liquid may also contain other additives which are also used for other polymers spun by the Wet spinning method; for instance: coloring agents, pigments, heat stabilizers, dye afiinity aids, softening agents, spinning aids, et cetera. Examples of dye afiinity aids are sulphonated polymers as described in the French Patent No. 1,361,067 and other conductive polymers as described in the Netherlands patent application Nos. 64-11681 and 293,623. Further suitable compounds are those containing groups that react with coloring agents, such as polyvinylpyrrolidone, et cetera. Of course, such groups can also be provided in the PPO to be spun; it is, for instance, possible to spin a sulphonated PPO.

It is possible also to incorporate in the spinning liquid polymers other than PPO such as polycarbonate, polyethyleneglycolterephthalate, polyethylene, polypropylene, polybutadienestyrene et cetera. In this respect polystyrene occupies a very special place, because it can be mixed with PPO homogeneously, and threads made from mixtures of PPO and polystyrene have very remarkable and attractive properties. It is true that woven and knitted fabrics made from PPO threads are highly resistant to creasing, but any creases formed in the fabrics cannot be removed by ironing except with great difficulty. Woven and knitted fabrics made from threads of mixtures of PPO and polystyrene are very crease-resistant, and any creases can be readily removed by ironing. Moreover, threads made from mixtures of PPO and polystyrene are cheaper than threads made from PPO. The amount of polystyrene in the mixture of polymers may be up to 70% of the total weight. In the case of higher percentages of polystyrene the mixture can still be spun, but the strength of the threads is reduced considerably.

It is preferred that the PPO spun according to the present invention has a relative viscosity, measured in a 1% by weight solution in benzene at 30 C., which is in the range of from 1.6 to 4.2. The most favorable results are obtained if this relative viscosity is in the range of from 2.5 to 3.5. Polymers having higher viscosities than 4.2 may give rise to spinning difliculties, whereas in general polymers having a relative viscosity lower than 1.6 give yarns the strength of which is insufficient for some applications.

Threads consisting of a homogeneous mixture of PPO and polystyrene have not been described before. They form part of the present invention.

As mentioned before, the coagulation bath should consist of 5 to 90% by volume of an aliphatic halohydrocarbon and 95 to by volume of a non-solvent for the polymer, which nonsolvent is miscible with the halohydrocarbon. The ratio in which these liquids are present in the coagulation or spinning bath is dependent on the nature of these liquids. For instance, the use of a non-solvent which has a strongly coagulating effect on the polymer will call for the presence in the mixture of a larger amount of the halohydrocarbon than the use of a non-solvent which has only a slight coagulating effect on the polymer.

For various combinations of halohydrocarbons and nonsolvents, the following optimum ratios are given.

Although optimum results are obtained if use is made of spinning baths having the above-mentioned ratios, reasonably good results are obtained if use is made of different values.

By preference, use will be made of a coagulation bath which consists of to 80% by volume of the halohydrocarbon and 85 to by volume of the liquid in which the polymer is insoluble.

Monovalent aliphatic alcohols having not more than 5 carbon atoms give very good results, so that the use thereof as a non-solvent is preferred.

A chloroform-containing spinning solution gives very favorable results if it is made up of 40% by volume of chloroform and 60% by volume of ethanol, so that the use of such a mixture is preferred. With the aid of a spinning bath of said composition a magnificent yarn is obtained of which the component filaments have a round crosssection.

The spinning bath may contain further additives, such as other liquids or dissolved solid substances imparting special properties to the yarn or facilitating the spinning process.

Threads manufactured by the process according to the present invention, if they have a linear density lower than 0.3 tex, often show a very attractive crimp. (The reference to tex is to yarn titre wherein l tex=l gram/ 1000 meters, pursuant to the recommendations of B.I.S.F.A.) In the case of higher linear densities crimped threads may be obtained by ensuring that the speed at which the thread is withdrawn from the spinneret is higher than the speed at which the spinning liquid is extruded through the spinneret orifices. The degree of crimp can be increased even further by subjecting the dry thread to a drawing process and then allowing it to relax.

To improve the properties of the yarn obtained it is recommended that after the yarn has left the coagulation bath it be passed through a second bath which substantially consists of a non-solvent for the polymer which is miscible with the halohydrocarbon used, such as ethanol. In this second bath part of the halohydrocarbon still present in the threads is removed therefrom, which increases their strength and improves their drawing properties, so that in the end a yarn having very favorable properties may be obtained.

In some cases it is of advantage if the second bath contains a salt, for instance: sodium acetate.

.It has been found that a similar effect to that obtained by using a second bath may be produced by having a nonsolvent for the polymer, which non-solvent is miscible with the halohydrocarbon used, drip onto the yarn after it has left the spinning bath; this method is to be recommended because of its simplicity.

The last-mentioned treatment is preferably carried out on the first roll with which the yarn comes into contact after it has left the spinning bath.

After the yarn has left the coagulation bath and by preference after a passage through said second bath or a treatment, as described above, with a non-solvent for the polymer, the yarn is drawn for the purpose of improving its properties. The most favorable results are obtained if the threads are drawn while still in the wet state; and the drawing process is therefore preferably carried out immediately after the above-mentioned treatment with a nonsolvent.

Prior to the drawing process compounds may be applied to the surface of the yarn which are incorporated therein during drawing. Such a technique in and of itself is described for threads of other polymers, for instance, in French Patent Nos. 1,089,381 and 1,236,688.

In this way it is possible, for instance, to effectively incorporate in the yarn stabilizers such as compounds protecting the yarn from decomposition under the influence of light and/or oxygen; for instance: 2,4-dihydroxybenzophenones or Z-mercaptobenzimidazole.

It is preferred that this introduction of stabilizers into the yarn during drawing thereof be carried out by incorporating these compounds in the non-solvent for the polymer with which the yarn is contacted after it has left the coagulation bath.

It has been found that protection from decomposition under the influence of light is particularly effective if an ultra-violet light stabilizer is incorporated in a polymer which is provided around the yarn as a sheath. This process, which is in and of itself is known in the case of other yarns, gives particularly favorable results in the case of PFC yarns. The spun threads are, preferably prior to the drawing process, wetted with a solution of a polymer such as cellulose acetate, polyvinyl acetate, polymethylmethacrylate, polyacrylic acid, polyvinyl alcohol, polyacrylonitrile, et cetera, in a solvent which also contains the desired stabilizer. After the solvent has been evaporated or the polymer precipitated by means of a coagulant, the stabilizer is present in the polymer sheath thereby formed on the PPO yarn. Needless to say, by the choice of the polymer and the substances incorporated therein it is possible also to modify other properties of the PPO yarn, such as its adhesive power, dye affinity, hydrophilicity, color electrostatic charging, et cetera.

A yarn having very special properties may be obtained if, after the thread has left the spinning bath, and while it still contains 5 to 50% by weight of the halohydrocarbon used as solvent, it is rapidly brought to a temperature between C. and the melting point of the thread. As a result, the solvent present in the thread evaporates more or less explosively, so that small cavities are formed in the thread and the thread becomes very bulky. in this way the thread is given a number of properties which make it very suitable for use in special applications.

Owing to its low specific gravity, a thread thus manufactured is very suitable for the manufacture of very light fabrics which have a satisfactory covering power. On account of the nature of the polymer, these light fabrics are highly resistant to creasing, so that they can be washed in boiling water. This combination of favorable properties makes it possible to manufacture from these threads textile products showing such favorable properties as cannot be obtained using any of the hitherto known fibrous products. These bulky threads are particularly suitable to be used for the manufacture of light-weight wash and wear garments.

Heating the thread to above 100 C. may be effected by any means, for instance by means of infrared rays, a stream of hot gas, a hot liquid bath, or a heated surface such as a hot drawpin.

Preferably, heating is carried out by passing the thread through a second bath, which should in this case have a temperature above 100 C. This second bath may consist of any liquid that can be heated to the desired temperature and which does not seriously attack the thread during the treatment thereof. Examples of suitable liquids are silicone oil, ethylene glycol, glycerol, Woods alloy, et cetera.

As very favorable results are obtained with glycerol, the use thereof is to be preferred. Any glycerol that sticks to the thread after it has left the bath may be removed in a simple manner by washing with water.

The bulky yarn manufactured in the above-indicated manner is bulky especially in the core. The sheath is relatively smooth, so that the yarn may be processed with excellent results on the usual textile machines.

To improve the strength of the bulky thread, it may, of course, be subjected to a drawing process. This drawing may take place before or after the thread has been treated in the hot bath. However, as the most favorable results are obtained if drawing takes place when the thread is in the hot bath, this method of drawing is to be preferred.

The thread, when it is being heated to a temperature above 100 0., should contain 5 to 50% by weight of halohydrocarbon calculated on the dry thread. If it contains less than 5% by weight, the thread will not be bulky. If the thread contains more than 50% by weight, its strength is, during heating, reduced so considerably that the process is no longer practicable. So far as both the quality of the resulting thread and the practicability of the process are concerned, the most favorable results are obtained if the thread contains between 12 and 18% of the halohydrocarbon, so that such a percentage is to be preferred.

If the thread is heated in a second bath, the temperature of said bath may vary between relatively wide limits. In general said temperature will be chosen at least 80 C. higher than the boiling point of the halohydrocarbon used as the solvent. Of course, the upper limit of the temperature range is at the point where the thread loses so much of its strength that it can no longer be passed through the hot bath.

In the above-described way it is possible to manufacture from PPO hitherto unknown threads having a specific gravity between 0.2 and 0.8. These novel threads form part of the present invention.

The above-described technique may also be used for the manufacture of threads from mixtures of PPO and polystyrene; such threads manufactured from a homogeneous mixture of PPO and polystyrene and having a specific gravity between 0.2 and 0.8 also form part of the present invention.

The yarns obtained according to the present invention have the advantages over any previously known yarns that without the incorporation therein of delustering agents they show a very attractive dull luster and that they may be processed to woven and knitted fabrics which have a high crease resistance. Upon microscopic examination it can be seen that, also if the yarn has after spinning not been subjected to a heat treatment, it is more or less porous.

It is noteworthy that from the same material, for instance by dryspinning, a yarn is obtained which has a completely different appearance and is not porous.

Owing to the remarkable appearance and the great suppleness of the yarns obtained according to the present invention, they are suitable for the manufacture of a wide variety of high-class textile products. The appearance of woven fabrics composed of these yarns very closely resembles that of natural silk fabrics.

The present invention will be further described in the following examples which are given merely by way of illustration of this invention.

Example -I 20 parts by weight of poly-2,G-dimethyI-paraphenylene ether having a relative viscosity of 2.10 (measured on a 1% by weight solution in benzene at 30 C.) are dissolved in 150 parts by weight of chloroform. After the polymer has dissolved, the resulting solution is allowed to stand for a few hours, after which it is filtered.

The spinning solution is extruded by means of a gear pump through a spinneret with 20 orifices microns in diameter into a coagulation bath consisting of a mixture of 45% by volume ethanol and 55% by volume chloroform.

The temperature of the spinning solution and of the coagulation bath is 20 C.

The spinning solution is extruded through the spinning orifices at a rate of 11 meters/minute. In the coagulation bath the extruded jets of spninning solution coagulate to form a thread which is drawn off from the spinneret at a rate of 11 meters per minute.

The length of the coagulation bath is cm. After the thread has left the coagulation bath, it is transported through a second bath, which consists of ethanol. The length of this second bath is 10 cm. The speed of the thread in this bath is the same as in the coagulation bath.

After the thread has left this second bath, the thread, which is still wet, is drawn to increase its length by 200% between two rolls which rotate at different speeds. To this end the yarn passes over this second roll at a speed of 33 meters per minute. After the yarn has left this last roll it is wound and subsequently dried for 16 hours in vacuo at 80 C.

The yarn obtained has a round cross-section, a strength of 32 g.. tex and an elongation of 28%.

A knitted fabric made up of this yarn is very supple, has a very attractive dull luster and shows a high degree of crease resistance, also after washing in water of 95 C. In this last-mentioned respect the yarn is far superior to hitherto known textile starting materials, such as natural fiber materials, polyamides or polyesters.

Example II A solution is prepared of 30 parts by weight poly-2,6- dimethyl-paraphenylene ether in parts by Weight chloroform, to which solution 0.6 part by weight 2,4-dihydroxybenzophenone is added.

After filtration this spinning solution is, in the manner indicated in Example I, spun into a coagulation bath consisting of 40% by volume ethanol and 60% by volume chloroform.

The thread formed in the coagulation bath is further treated as indicated in Example I. The resulting thread has a strength of 38 g./tex and an elongation of 22%.

Example 111 A yarn is spun in the manner described in Example I, except that this time no second bath is used. Instead, after the yarn has left the coagulation bath, ethanol is dripped on to it.

Apart from that, the procedure is the same as that described in Example I. The resulting yarn has a strength of 30 g./tex and an elongation of 29%.

Example IV A yarn is spun in the manner described in Example 1, except that the coagulation bath consists of a mixture of by volume methanol, 15% by volume ethanol, 15% by volume isopropanol, and 55% by volume chloroform.

The resulting thread is hardly or not at all different from the thread obtained according to Example I.

Example V A yarn is spun in the manner described in Example I. This time however, the solvent contained in the spinning solution consists of 50% by weight chloroform and 50% by weight dichloromethane, and the coagulation bath consists of a mixture of 46% by volume n-butanol and 54% by volume dichloromethane.

The resulting thread differs hardly, if at all, from the thread obtained according to Example I.

Example VI A yarn is spun in the manner described in Example I, except that the polymer solution contains 6% by weight (calculated on the weight of the polymer) of a copolymer of 70% by weight butadiene and 30% by weight styrene. In this case the second bath contains 4% by weight sodium thiosulphate in addition to the ethanol. Part of the sodium thiosulphate is incorporated in the thread during drawing. The thread is then passed through an acid bath in which the thiosulphate decomposes and sulphur deposits in the thread. The sulphur-containing thread is heated to 150 C., as a result of which the synthetic rubber present therein is vulcanized. The thread obtained has mechanical properties which are equal to those of the thread obtained according to Example I, but its solubility in organic solvents is considerably lower.

Example VII A thread is spun in the manner indicated in Example I, except that in this case use is made of a spinning tube through which the spinning bath liquid passes at a speed which is 80% of that of the thread. The diameter of the spinning tube is 16 mm. and the length is 100 cm.

The thread is withdrawn from the first bath at a speed of 40 meters/minute. And after the thread has left the second bath, it is drawn at a speed of 100 meters/ minute.

The final thread has a strength of 25 g./tex and an elongation of 20%.

Example VIII A yarn is spun in the manner described in Example I. This time, however, use is made of a second bath consisting of a solution of 3% by weight sodium acetate in butanol. The temperature of this second bath is 100 C.

The speed of the last roll is not 33 meters/minute, as in Example I, but 40 meters/minute.

The resulting yarn has a strength of 45 g./tex and an elongation of 19%.

Example IX A solution of 22 g. PPO in 100 ml. chloroform is extruded through a spinneret provided with an orifice 300 microns in diameter. The extrusion rate is 1.5 meters per minute. The spinneret is mounted in a spinning bath which has a length of 100 cm. and a temperature of 20 C. and consists of a mixture of 40% by volume chloroform and 60% by volume ethanol. After the thread formed has left this bath, it is given six Wraps around a combination of a driven first roller and a guide pin, after which it is passed through a glycerol bath having a temperature of 140 C. The thread is'withdrawn from the bath by means of a driven second roller, of which the eripheral speed is five times that of the first roller, guided through an ethanol bath and is then, by way of a third roller, of which the peripheral speed is 1.1 times that of the second roller, wound on a bobbin and dried. The thread thus obtained has a linear density of 1.6 tex, a strength of 24 g./tex, an elongation of 30%, a porosity of 60% and a specific weight of 0.4.

Example X A thread is spun in the way described in Example IX,

except that use is made of a spinneret provided with 20 round orifices microns in diameter. The composition of the spinning bath now is 30% by volume chloroform and 70% by volume ethanol. The peripheral speeds of the first, the second and the third rollers now are 10, 35 and 35 m./min., respectively. The temperature of the hot glycerol bath now is 150 C.

The yarn obtained has a linear density of 9 tex, a strength of 15 g./tex, an elongation of 20% and a specific weight of 0.4.

Example XI A solution in ml. chloroform of 22 g. PPO having a relative viscosity of 2.55 (measured on a 1% by weight solution in benzene at 30 C.) is extruded through a spinneret provided with one orifice 200 microns in diameter into a spinning bath consisting of 40% by volume chloroform and 60% by volume ethanol. The temperature of the spinning bath is 20 C. and its length is 100 cm. The thread formed in the spinning bath is withdrawn therefrom at a rate of 3 TIL/min. by way of a combination of a driven first roller and guide pin around which the thread is given 13 wraps, after which it is guided to a second combination of a driven roller and a guide pin, around which the thread is given eight Wraps. The peripheral speed of the second roller is 10 m./min. From this second roller the thread is passed into a glycerol bath having a temperature of C., and then by way of a third driven roller (speed 13 m./min.) into an ethanol bath. Subsequently, the thread is wound onto a bobbin and dried. The thread obtained has a linear density of 1.6 tex, a strength of 20 g./tex, an elongation of 35%, a porosity of 60% and a specific weight of 0.4.

Example XII Of a mixture of PPO and polystyrene (of which the relative viscosities measured on 1% by weight solutions in benzene at 30 C. are 3.2 and 2.4, respectively) 2400 grams are dissolved at room temperature in 10 1. chloroform. The solution thus obtained is filtered and serves as spinning solution.

The spinning solution is extruded by means of a gear pump through a spinneret with 20 orifices 80 microns in diameter into a coagulation bath contained in a trough. The coagulation liquid consists of a mixture of 40% by volume chloroform and 60% by volume ethanol, and has a temperature of 20 C. The spinning solution is extruded through the spinning orifices at a rate of 10 meters/minute. In the coagulation liquid the extruded jets of spinning solution coagulate to form a thread made up of 20 filaments. By means of a roller the thread is drawn off from the spinneret at a rate of 11 meters/minute. The thread passes through the coagulation bath over a distance of 100 cm.

After the thread has left the roller it is transported through a second bath of 20 C., consisting of ethanol in which 0.15% by weight sodium acetate has been dissolved. The distance over which the thread is passed through this second bath is 40 cm.

In this bath the thread is drawn to increase its length by The thread (8 tex) is then wound on to a bobbin and dried for 16 hours in vacuo at 80 C.

In Experiments :1 to i the percentage of PPO in the mixture is varied from 100% to 20%. The results are tabulated below.

TAB LE Percent PPO Poly- Percent Breaking Elongation styrene polystrength at break, in grams styrene (g. /tex) percent The table shows that a percentage of 70% Polystyrene still gives threads having a satisfactory strength.

The threads are uncrimped, have a round cross-section and a low specific gravity. Knitted fabrics made up of the threads obtained in Experiments b to i are very supple, have an attractive dull luster, are white in color and show a high degree of crease resistance; small creases, if any, can be ironed out.

When these fabrics are dyed at 95 C., or when they are washed in water of this temperature, they do not crease. When they are cut into fibers which are processed into a spun yarn, there is obtained a non-pilling spun yarn.

Example XIII Experiment d of Example XII is repeated. In this case, however, 1680 g. PPO and 720 g. polystyrene are dissolved in 10 l. trichloroethylene instead of in chloroform, and the coagulation bath consists of 30% by volume trichloroethylene plus 70% by volume ethanol instead of 40% by volume chloroform plus 60% by volume ethanol.

The thread obtained has a breaking strength of 40.2 g./ tex and an elongation of 20.6%. In other respects the thread is not different from that obtained in Example XIId.

Example XIV Example XIId is repeated. In this case, however, use bath and the second bath contain methanol instead of ethanol.

The thread obtained has a strength of 40.9 g./tex, a round cross-section and it shows no crimp. In other respects this thread is the same as that obtained in Example XIId.

Example XV Example XII'd is repeated. In this case, however, use is made of a spinneret with 100 orifices, and the thread is drawn off from the spinneret at a rate of m./min. In the coagulation bath the thread is consequently drawn to a considerable degree, since the spinning solution is extruded through the orifices at a rate of 10 m./min.

In the second bath the thread is drawn to increase its length by 85%.

The dried thread shows a satisfactory crimp, which may even be improved by drawing the thread, while in the dry state, by 15%, after which the thread is allowed to relax.

A knitted fabric made up of this thread does not crease. Woven fabrics made up of staple fibers obtained by cutting the thread are bulky and non-pilling.

Example XVI 1300 g. poly-2,6-dimethyl-paraphenylene ether having a relative viscosity of 3.2 and 700 g. polystyrene having a relative viscosity of 2.4 are dissolved at 50 C. in 101. 1,2- dichloroethane.

After the spinning solution of 50 C. has been filtered, it is extruded through a spinneret with orifices 80 microns in diameter into a coagulation liquid contained in a trough. The coagulation liquid consists of a mixture of 40% by volume 1,2-dichloroethane and 60% by volume ethanol, and has a temperature of 35 C. The spinning solution is extruded through the spinning orifices at a rate of 10 meters/minute. By means of a roller the thread obtained is drawn off from the spinneret at a rate of 11 meters per minute. After the thread has left the roller it is passed through a second bath having a temperature of 40 C. and consisting of ethanol. In this bath the thread is drawn to increase its length by 155%. The thread (8 tex) is then wound onto a bobbin and dried in vacuo at C.

The thread (8 tex) is uncrimped and has a strength of 34 g./tex. Fabrics Woven or knitted from this thread or from spun yarns made therefrom are highly resistant to creasing, may be ironed and do not pill.

Example XVII Example XVI is repeated. However, in this case the poly-2,6-dimethylparaphenylene ether and the polystyrene are dissolved at 20 C. in 1,1,2,2-tetrachloroethane.

The spinning bath of 20 C. consists of 40% by volume 1,1,2,2-tetrachloroethane and 60% by volume ethanol. The freshly spun thread is drawn in the second bath to increase its length by 180% The thread obtained (8 tex) shows no crimp and has a strength of 38 g./tex. It can excellently be processed to crease-resistant, supple woven and knitted fabrics which do not pill.

Example XVIII 2200 g. poly-2,6-dimethylparaphenylene ether having a relative viscosity of 3.2 and 770 g. polystyrene having a relative viscosity of 2.4 are dissolved in 10 l. of chloroform at 20 C. After filtration, the spinning solution of 20 C. is extruded through a spinneret with 20 orifices 80 microns in diameter into a coagulation liquid contained in a trough. In Experiments a to g the coagulation liquids of 20 C. respectively contain, in addition to chloroform, as non-solvents: 20% by volume acetone, by volume petroleum ether (boiling point 6080 C.), 60% by volume dimethyl formamide, 60% by volume ethyl acetate, 60% by volume di-n-butyl ether, 50% by volume acetic acid and 60% by volume methyl ethyl ketone.

The spinning solution is extruded through the spinning orifices at a rate of 10 meters/minute. By means of a roller the threads are drawn off from the spinneret at a rate of 11 meters per minute. After the threads have left the roller they are passed through a second bath of 40 C. consisting of ethanol and 0.15% by weight sodium acetate. In this bath the threads are drawn to increase their length by 180%, 200%,180%,160%,170%,l80% and 180%, respectively. Thereupon, the threads (8 tex) are wound onto bobbins and dried in vacuo at 80 C. They show no crimp and are round in cross-section.

While specific examples of preferred methods and products embodying the present invention have been set forth above, it will be understood that many changes and modifications may be made in the methods of procedure and in the products without departing from the spirit of the invention. It will therefore be understood that the examples cited, the particular proportions and methods of operation, and the products set forth above are intended to be illustrative only, and are not intended to limit the scope of the invention.

What is claimed is:

1. A process for the wet spinning of threads from poly- 2,6-dirnethyl-paraphenylene ether which comprises ex trnding a spinning solution of said polyether in an aliphatic halohydrocarbon into a coagulation bath consisting essentially of 5 to 90% by volume of said halohydrocarhem and to 10% by volume of diethyl ether.

2. A process as defined in claim 1 wherein said coagulation bath consists essentially of 15 to 80% by volume of halohydrocarbon and 85 to 20% by volume of diethyl ether.

(References on following page) 1 1 References Cited 3,342,892

UNITED STATES PATENTS 4/1963 Notarbartolo et a]. 264--38 X :3 23 11/1963 Fukushima et a1. 264184 X 5 11/ 1965 Blanchard et a1. 11/1965 Fox.

6/1966 Stamatofi 26033.8 X

2/ 1967 Hay.

8/1967 Gord et a1 264-38 X 10 26047; 264203 12 Laakso et a1. Fukushima et a1 264-184 Gowand 264343 X Holich.

JULIUS FROME, Primary Examiner J. H. WOO, Assistant Examiner US. Cl. X.R. 

